The invention relates to a dishwashing machine with a washing compartment and a drying unit, comprising an absorption column with a drying agent which can be reversibly dehydrated, with an air circulation loop through the washing compartment and the drying unit and with temperature detection of the circulating air. The invention further relates to a drying method for dishwashing machines with a drying unit and an air circulation loop between said drying unit and the washing compartment, in which a temperature profile of the circulating air is recorded and the drying is terminated upon a predefined value being reached.
Dishwashing machines with a drying unit can have a drying agent which can be reversibly dehydrated as water-absorbing material. They make use of the characteristic of the zeolite whereby heat is emitted upon the absorption of water as a consequence of the absorption reaction. The more water the zeolite absorbs, the higher its temperature rises. This fact can be used to detect the moisture content in the air circulation loop of the dishwashing machine and thus the degree of drying of the crockery. Control of the drying process, which is based on the detection of the temperature and thus indirectly on the humidity of the air, is considerably more precise than time-based control, as it is oriented toward the actual drying conditions in the dishwashing machine. These can, for example, fluctuate sharply as a result of loads of different weight or density in the dishwashing machine. Sequential control of this kind is, for example, described in DE 10 2005 004 097 A1. It is further known from DE 10 2005 004 097 A1 for the temperature to be detected as close as possible to the heat source, that is downstream of the absorption column or in the water-absorbing material itself. The high temperatures prevailing there do, however, call for specially designed, more expensive temperature sensors.